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NUCLEUS IS OF VIRAL ORIGIN? "I contend that the cell nucleus itself is of viral origin. The nucleus may have evolved from a persisting large DNA virus that made a permanent home within prokaryotes." This has support In sequences of DNA polymerase genes but remains debated. http://www.scientificamerican.com/article.cfm?id=are-viruses-alive-2004&page=3 View in LinkedIn

ANIMALS VERSUS PLANTS. "While studies in animal systems show that a gain of new expression patterns is rare relative to changes in the timing or level of gene expression, the expansion or restriction of spatial expression domains, or the loss of expression features, gene duplication and rampant polyploidy that are inherent to plants enables the possibility for a gain of new expression to likewise provide a considerable source of developmental variation." https://lnkd.in/dD4GcAS View in LinkedIn

VIRUSES ARE GENETIC INNOVATORS. "The huge population of viruses, combined with their rapid rates of replication and mutation, makes them the world’s leading source of genetic innovation: they constantly “invent” new genes." https://lnkd.in/dQ2abpA View in LinkedIn

WIDE SUBTLETY OF OUTCOMES. "When a gene acquires a new TF binding site, it can alter its expression domain either by adding new expression or by repressing expression in certain locations, times or under certain conditions." (TF = transcription factors). https://lnkd.in/dD4GcAS View in LinkedIn

VIRUSES BUILD GENOMES of other species, at a significant rate. "Their contribution to mammalian genomes is probably underestimated because TEs have diverged beyond recognition. Most of them are inactivated by mutations so that they cannot replicate. They make up one third of our genome." (TE = transposable elements). https://lnkd.in/eGaw2Kq View in LinkedIn

OTHER MECHANISMS. "Cis-regulatory changes can evolve de novo by accumulation of mutations in cis-regulatory elements, or can be altered by increases in number and function of transcription factor (TF) binding sites following gene or whole-genome duplication events." https://lnkd.in/dD4GcAS View in LinkedIn

NETWORK BUFFERING. "The same benefits of modularity that were evoked to hypothesize why cis-regulatory changes would be less pleiotropic than functional changes apply as well to the modularity of GRNs as effectors of gene regulation and expression, with the GRN acting as a buffer against any widespread negative effects of a coding mutation in a developmental gene." (GRN = gene regulatory networks). https://lnkd.in/dD4GcAS View in LinkedIn

SPARED BY REDUNDANCY. "Because of modularity in plant development and redundancy in GRNs underlying developmental processes, however, a change in a protein sequence may not have the massive negative pleotropic effects that were once considered to eliminate such changes from playing a role in developmental evolution." (GRN = gene regulatory networks). https://lnkd.in/dD4GcAS View in LinkedIn

REGULATORY MUTATIONS. "Unlike with functional mutations, regulatory mutations would not impact the physical interactions and function of the encoded protein, enabling essential metabolic or cellular functions to proceed." https://lnkd.in/dD4GcAS View in LinkedIn

MORPHOLOGICAL GENE MUTATIONS. "Mutations in regulatory regions were thus thought to be the main force for morphological evolution, as changes in gene regulation impacting timing and/or position of gene expression were likely to be better tolerated as a result of their more subtle effects in a restricted set of tissues during development." https://lnkd.in/dD4GcAS View in LinkedIn